1. Field of the Invention
The present invention relates to psychological testing. More particularly, the present invention relates to a computer program and a method for creating non-verbal test items to target levels and cognitive sources of item difficulty for psychological intelligence tests.
2. Description of Prior Art
Common intelligence tests use non-verbal items to measure examinees' complex reasoning and judgment skills, which have been shown to best reflect intelligence. Matrix completion items are often viewed as the single best item type to measure intelligence, but other item types, such as, figural analogies, figural series, figural classifications, cube folding, and object assembly also appear on intelligence tests. These item types are typically administered in a multiple choice format where the task is to select the alternative that fulfills the relationships defined in the item.
For example, matrix completion problems present test subjects with a matrix of objects, each object comprising specific attributes. Each attribute may be shared with one or more of the other objects, in specific combinations, thereby rendering each object unique.
Test subjects are also presented with a list of response alternatives, which comprises a number of objects similar to the objects in the matrix. One of the objects in the list of response alternatives comprises attributes, in specific combination such that it completes the matrix.
The matrix and the list of response alternatives, in combination, form a non-verbal test item. A number of items are used in each test. Items are typically created by human item writers guided by loose sets of specifications concerning desired attributes. Quite often, item writers are shown previous tests and told to make items like those on previous tests. Item writers may also be given general guidelines about certain attributes and desired difficulty, particularly in relation to previous tests.
However, items are largely unspecified and actual item creation depends on the skill and judgment of individual item writers. While item writers may use computer drawing programs to develop arrangements of objects for each item created, item writers choose not only specific objects, but also their arrangement. Since item writers are generally artists, psychometric properties, such as item difficulty, are beyond their scope and can only be known after empirical tryouts on appropriate groups of test subjects.
Furthermore, item creation has not been influenced by recent research findings. Several studies provide a basis of algorithmic item creation, which lessens the role of human item writers. In algorithmic item creation, item writers must still create each item, but item creation is controlled by a more elaborate set of specifications. These specifications contain specific cognitive sources of item difficulty supported by research on cognitive models for various item types. Therefore, item difficulty levels may be predicted reasonably well for such items.
However, these specifications are not complete and human item writers are still required to choose objects and attributes, and then combine them into each item. As in standard item creation practices, algorithmic item creation still depends on human skill and judgment, but to a lesser extent. Also, item creation remains time consuming and items are not available immediately. Therefore, items cannot be quickly created to specifically target levels and cognitive sources of item difficulty.
Accordingly, there is a need for an improved method of creating non-verbal test items to target levels and cognitive sources of item difficulty that overcomes the limitations of the prior art.